js 图片转换问题 高手帮忙

<script language="javascript" type="text/javascript">
//<![CDATA[

function displaylarge(pix,id) {
// check if this image is already active
obj = document.getElementById('thumbhref' + id);
if (obj) {
if (obj.className == "Active") return;
}

for (var i = 0; i < 5; i++) {
obj = document.getElementById('thumbhref' + i);
if (obj) obj.className = "NotActive";
}
obj = document.getElementById('thumbhref' + id);
if (obj) obj.className = "Active";

new Effect.Fade('largepic', { duration: 0.15, from: 1.0, to: 0.10 });
fadingTimer = setTimeout( function() { displaylarge_faded(pix); }, 200);
}

function displaylarge_faded(pix) {
loadingTimer = setTimeout( function() { displaylarge_loading(); }, 100);

imgLoader = new Image();
src = "/images/" + pi